paint evaluation report - nh.gov

New Hampshire Department of Transportat¡on

Paint Evaluation Report

Portsmouth Memorial Bridge

ln-depth lnspection and Condition Report

Corrrxc CoxurroN ASSBSSMENT

or PonrsMourH-KrrrERY

Mnuonrnr, BnIDcE

Pnorucr No. 13678-E

Prepared For:

HDR Engineering, fnc.695 Atlantic Avenue,2nd Floor

Boston, MA 02111

Attn: Ms. Loretta Doughty, Structural Section Manager

Prepared Bv:

KTA-TATOR, rNC.115 Technology Drive

Pittsburgh, Pennsylvania 1527 5(412) 788-1300 - phone

(412) 788-1306 - faxwww.kta.com

Robert LantermanProject Professional

November 20,2009

RSL:MPR:kmmJN290673HDR- Memorial Bridge Report.doc

TABLE OF CONTENTS

NOTICE: This report represents the opinion of KTA-TATOR, lNC. This report is issued in conformancewith generally accepted industry practices. While customary precautions were taken to verify theinformation gathered and presented is accurate, complete and technically correct, this report is based

on the information, data, time, materials, and/or samples afforded. This report should not be

reproduced except in full.

INTRODUCTION

In accordance with an agreement between HDR Engineering, Inc. (HDR) and KTA-Tator,ktc. (KTA), KTA has completed a coating condition assessment of the Memorial Bridge for thePortsmouth-Kittery 13678-E Project. The assessment was performed by Robert Lanterman ofKTA on September 29,2009. The purpose of the assessment was to determine the condition ofthe existing coating systems applied to the structures. The following report includes the resultsof the field investigation, a discussion of coating rehabilitation options, and opinions of probablecost for repainting. Photographs of typical coating conditions observed are also included.

SUMMARY

The coating system applied to the bridge steel was in poor condition overall. Corrosionwas observed throughout the structure. Stratified corrosion, pitting, and section loss was alsoobserved. Based on the overall percent of visible corrosion and the adhesion test results,spoVzone repairs and overcoating would not be recommended. Total coating removal andreplacement would be recommended for the entire bridge.

Laboratory testing reported detectable concentrations of lead present in the existingcoatings on the bridge. The presence of lead will require the implementation of specialsafeguards to protect workers, the environment, and the public during any painting operations as

well as the management of hazardous waste.

BACKGROUND

The Memorial Bridge is through truss lift bridge that canies US I across the PiscataquaRiver. The bridge is 1783' in total length (including the Kittery approach) and was constructedbetween 1920 and 1923. The specific coating maintenance history was not available.

FTELD INVESTIGATION

Mr. Robert Lanterman of KTA performed the field coating condition assessment onSeptember 29,2009.

Access to the bridges was made available by Ms. Loretta Doughty of HDR, InspectionTeam Leader Mr. Justin Stewart of HDR, and Mr. Gene Popien the Bridge Maintenance Managerfor the New Hampshire DOT. The below deck portions were accessed at the piers. The lift spanwas fully raised to provide access to the lift span towers. Access to the Kittery approach wasmade from grade below the structure.

HDR Engineering, Inc.Memorial Bridge

November 20,2009JN290673

Testing Protocol

The following tests were performed in order to determine the condition of the existingcoatings on the structure:

Visual - A visual assessment of the coated surfaces was conducted to determine the extent,

location, and any noticeable patterns of coating deterioration and/or corrosion. Assessments

were made in general accordance with SSPC-VIS 2, Standard Method of Evaluating Degree

of Rusting on Painted Steel Surfaces.

Coating Thickness - Dry film thickness was determined using a Positector 6000. The

Positector 6000 is a portable, battery operated, digital coating thickness gage, which non-

destructively measures non-magnetic coating thickness over ferrous substrates using a

magnetic principle. Calibration was verified prior to and after use with the National Instituteof Standards and Technology (NIST) thickness standards.

Number of Coats - The number of coats present and the thickness of each were determined

using a Tooke Gage Mark IV with a2X-cutting tip. This hand-held gage with a microscope(50X) destructively measures the thickness of each coat in multi-coat systems (up to 50 mils).Observation of a coating cross-section created with a cutting tip of known angle shows

coating thickness and can be used to detect intercoat contamination, voids, underlying rust,

mill scale, and pinholes.

Adhesion - Adhesion testing was conducted in general accordance with ASTM D3359,"Measuring Adhesion by Tape Test." Method A of this standard was utilized. Method Ainvolves cutting an "X" through the coating down to the substrate using a Íazor knife,followed by the application of pressure sensitive tape (Permacel 99). The tape is then sharply

removed from the X-cut and the amount of coating detached is then rated in accordance withthe ASTM rating scale. Typical ratings of 4A to 5A are considered by KTA to represent

good adhesion;2A to 3A represent fair adhesion, wtrile 0A to 1A represent poor adhesion.

Photographs - Photographs of typical conditions were taken and are included in this report.

Visual Observations

The coating system applied to the bridge steel was in poor condition. Approximately507o corrosion was observed over the surfaces of the steel members. The above deck portions onthe truss spans \ryere in poor condition. Corrosion was observed in the splash zone as well as theupper truss members.



Photograph 1 - Top chord portal Photograph 2 - Top surface of top chord

Photograph 3 - Top surface on top chord Photograph 4 - Fixed truss portion

The interior portions of the box members were in poor condition, with the amount ofcotrosion similar to the exterior portions. Pack rust was observed at the lattice bar connections.Section loss was observed on some of the rivet heads.



Photograph 5 - Corrosion on lattice Photograph 6 - Corrosion on interior portion

The coating on the below deck members was in poor condition. Increased corrosion

levels were observed under the open grating deck portions of the lift span. Areas of pack rust,pitting, and section loss were observed on the stringers and floor beams. Section loss was

observed on some of the rivet heads and stratified corrosion was noted on the bearing pin nuts.

Photograph 7 - Below deck on fixed truss

Photograph 9 - Corrosion on stringer

'¡ ¡4.

Photograph 10 - Section loss at floor beam



Photograph 6 - Corrosion on interior portion

Photograph 8 - Below deck on lift span

Photograph 11 - Section loss on rivets Photograph 12 - Section loss on bearing pin nut

The lift span towers were in poor condition overall. Corrosion was observed on the towermembers as well as the mechanical portions located on top of the towers.

Photograph 14 - Tower and counterweight

The Kittery approach spans were in poor condition overall. Corrosion was observed to beincreased on the fascia members and on the steel members adjacent to the deck drains.



Photograph 13 - Tower and counterweight

Photograph 15 - Cable sheave Photograph 16 - Cable sheaye

Photograph 17 - Kittery approach Photograph 18 - Fascia corrosion

Photograph 19 - Deck drain Photograph 20 - Abutment bearing

Total Drv Film Thickness (Positector)

Approximately 50 dry film thickness measurements of the total coating system were

taken throughout the accessible portions of the bridge. Thickness measurements ranged from 6mils to 27 mils with an aveÍage thickness of 14 mils.

Individual Coatine Thickness (Tooke Gaee)

Tooke gage tests were conducted on several bridge members. Field measurements

consistently found that 6 coats of paint were present in the test areas. The prime coat was orange

in color and2 to 3 mils in thickness. The intermediate coats were green in color and 3 to 4 milsin thickness, orange in color and 2 mils in thickness, green in color and 2 mils in thickness, and

orange in color and 2 mils in thickness. The finish coat was green in color and 2 to 3 mils inthickness.


6 November 20,2009JN290673

Adhesion

Approximately 15 adhesion tests were conducted on the accessible bridge surfaces. Thecoating in the areas tested was visibly intact. Adhesion ranged from 0A (poor) to 1A (poor), withan average rating of 1A (poor). Forced detachment during the testing occurred primarily as acohesive break within the prime coat.

Substrate ExamÍnation

The substrate was available for examination at all Tooke gauge and adhesion test areas.The substrate was covered with a layer of mill scale in the test areas.

Samples

The following five (5) coating samples were removed from the bridge for laboratorytesting.

Table 1- Sample Locations

Sample No. Member Location

7 Floor beam Below deck

8 Truss diagonal Fixed truss span

9 Sheave guard NH Tower

12 Truss vertical Lift span, splash zone

T3 Floor beam At expansion joint



LABORATORY INVESTIGATION

The laboratory investigation consisted of atomic absorption spectroscopy and ionchromatography. The methods of analysis and results of the investigation are provided below.

Atomic Absorption Spectroscopy

The Memorial Bridge Samples 7, 8, and 9 were analyzed for total lead, cadmium and

chromium in accordance with AOAC Method 974.02. Briefly, this method entails digestingsamples in acid, filtering and analyzing by flame atomic absorption spectroscopy. Results of the

testing are presented in Table 2, "Toxic Metal Content."

Table 2 - Toxic Metal Content

Sample No.Lead Content

lnnm)Cadmium Content

lnnm)Chromium Content

lnnm)

7 285,738 (28.6Vo) Non-Detectable 13,220 (l.3Vo)

8 251,290 (25.IVo) Non-Detectable 17,795 (l.8%o)

9 236,570 (23.7Vo) Non-Detectable 28,780 (2.9Vo)

Ion Chromatographv

Ion chromatography (IC) was performed on two (2) coating chip samples (Samples 12

and 13). The samples were weighed and then gently boiled in deionized water for forty-five (45)

minutes before being cooled and filtered. A Shimadzu Model LC-204D pump, CCD-104conductivity detector and a Shodex 424 anion column were used for the analysis. A water based

buffer solution, as recoÍrmended for the Shodex 424 coltmn was pumped through the system at

a flow rate of 1.0 milliliter per minute. A three (3) point calibration curve \ilas established usingstandards of known quantities of six (6) anions, which are listed in Table 3, "Results of ICAnalysis." Two (2) chromatograms are appended.

Table 3 - Results of IC Analysis

Sample No. Chloride

12 373 ¡tglg

I3 583 ¡rg/g

HDR Engineering,Inc.Memorial Bridge


DISCUSSION

General Discussion on Maintenance Paintine

The purpose of this coating assessment was to assess the condition of the existingcoatings on the structures and make recommendations for maintenance painting. Many factorsaffect the service life of a coating system. These include the type of coating originally applied,the type and quality of surface preparation, service environment, number of coats and filmthickness, and the history of maintenance painting activities.

If a particular coating has provided satisfactory corrosion prevention and remains inrelatively good condition, it is cost effective to extend the life ofthe system through overcoating,retaining as much of that original coating as possible. When the coatings are in poor condition, a

"full removal" strategy is used, which removes all existing coatings. This strategy effectivelyplaces the bridge at the beginning of a new maintenance painting cycle. Little work wilt berequired for at least 10 years, and then, it should involve only minor touch-up. This strategy,while safe and effective, is also expensive. A discussion of the various types of maintenancepainting activities follows.

Maintenance painting options for bridge structures fall into four main categories:(1) defenal of maintenance, (2) spot repairs, (3) spot repairs with full overcoats, and (4) completecoating removal and replacement.

Each of these options is progressively more complex and requires progressively morework. Correspondingly, each option also offers greater long-term protection to the structure, butat additional costs. 'When paints containing hazardous metals are present, the issues associatedwith removing these paints impact the decision making process.

Deferral of Maintenance

Maintenance painting can be deferred if the existing coating system is in good condition,if the service life of the structure is limited, or there is some other benefit for postponing thework. ff extensive corrosion is found and maintenance painting is deferred for a period of time,the level of surface preparation required to properly prepare the surface increasescorrespondingly, and if left unattended for too long, total removal will ultimately be required. Insome cases, when the structure is corroding extensively but is still structurally sound, painting isdeferred because the highest level of surface preparation (abrasive blast cleaning) is alreadyneeded, whether performed today or several years from now. The strategy in this case is toallocate the money to repair coatings on other structures that are not so badly deteriorated inorder to stop the corrosion from propagating to the point that total removal is the only option forthose structures as well.



Spot Repairs

Spot repairs, as the name suggests, involves surface preparation and coating applicationonly to the individual spots of corrosion or coating breakdown. The amount of coating being

removed is minimized, reducing the impact of hazardous materials handling, containment, and

worker protection when toxic metals are present. Spot repairs also serve to repair the existing

coating film only where it is needed, repairing the corroded areas and stopping the propagation ofthe breakdown. Coatings in essentially any condition may be spot repaired, but it is onlypractical when the level of breakdown is minor and somewhat isolated and covers a smallpercentage of the surface (e.g., 1 or 27o). A disadvantage of this approach involves aesthetics.

The repair spots are clearly visible.

A variation of this type of localized repair includes zone or area repairs. This involves

surface preparation and coating application over a larger area that exhibits more concentratedlevels of breakdown, but the work is limited to those areas. For example, the bearing areas ofgirders are often zone painted on either side of an expansion joint, without any significantpainting on the rest of the structure.

Spot Repairs with Full Overcoat(s)

The application of a full overcoat serves two primary purposes: the additional coat

provides additional banier protection and helps to seal minor defects that are not apparent whenconducting spot repairs. It also offers an improved appearance when compared to spot repairs.

The addition of the overcoat also adds complexity and cost to the overall project. The

complexity increases because a contractor must now gain access to all areas of the structure to

apply the full coat. The existing surface must also be thoroughly cleaned (i.e., power washed) to

remove chalk and surface debris. The adhesion of the existing coating must also be good and

sound; otherwise the stresses imparted by the overcoat can cause disbonding of the existing

system, especially under freezelthaw conditions. In some cases, two full overcoats are applied.This strategy is typically used when the amount of visible corrosion and coating deteriorationcovers less than l5Vo of the surface.

Total Coating Removal and Replacement

Total removal and replacement is the final option for maintenance painting. It is the mostcostly option (especially when removing existing coatings that contain toxic metals), but it offersthe greatest opportunity for long-term protection. All of the mill scale, rust, and paint are

completely removed and a new system with a new design life is applied. All paint containingtoxic metals is removed at the same time, eliminating hazardous metals from futureconsideration. This method also provides the most pleasing appearance.

When total removal and replacement is performed, a new maintenance cycle begins. Asthe coatings age and weather, isolated spot repairs will be required. Several spot repairs may be

made to the individual structure until a full overcoat is necessary. More spot repairs may then be

made and additional overcoats applied until extensive corrosion develops, significant coating



10

breakdown occurs, or the mechanical properties of the coatings (e.g., the adhesion) degrade to thepoint where additional work (spot touch-up or overcoating) is no longer practical. At this time,complete removal may again be required, but only after the maximum effective life of theoriginal coating system has been extended through the planned maintenance activities.

RECOMMENDATIONS

The coating system applied to the bridge steel was in poor condition overall. Corrosionwas observed throughout the structure. Stratified corrosion, pitting, and section loss was alsoobserved. Based on the overall percent of visible corrosion and the adhesion test results,spot/zone repairs and overcoating would not be recommended. Total coating removal andreplacement would be recommended for the entire bridge.

The specifications should require abrasive blast cleaning in accordance with SSPC-SP 10,"Near White Metal Blast Cleaning." The specifications need to recognize the presence ofchlorides and include provisions for remediating them (e.g., pressure washing, steam cleaning,blast cleaning the steel and allowing it to rust overnight followed by reblast cleaning, using a mixof course and very fine abrasives, use of chemical chloride removal solutions, and others).Chloride contamination can be a particular problem for bridges in areas where de-icing salts areused on the road surfaces, especially in areas below expansion joints and open decks. Chloridemust be removed for the surfaces prior to painting.

The recommended replacement coating system for these areas should involve three coats,consisting of an organic zinc rich prime coat, an epoxy intermediate coat, and a polyurethanefinish coat, with stripe coats of the primer and intermediate coats applied to edges, crevices,rivets, and other irregular surfaces. This is the most common bridge coating system used acrossthe country and is the most commonly tested system under AASHTO NTPEP (NationalTransportation Product Evaluation Program). Matty epoxy zinclepoxy/urethane systems are alsoapproved under the NEPCOAT (North East Protective Coatings Committee) program.

Dealine with Lead

Laboratory testing reported detectable concentrations of lead present in the existingcoatings on the bridge. The OSHA Lead in Construction Standard (29 CFR 1926.62) requiresthat controls be implemented if any detectable concentrations of lead are present. The OSHACompliance Directive issued for the OSHA Lead in Construction Standard, Instruction CPL 2-2.58, states that if an employer has appropriately tested for lead (e.g., tested all layers of paints orcoatings that may be disturbed) utilizing a valid detection method, and found no detectable levelsof lead, then the standard does not apply. Paints with detectable concentrations of lead requirethe contractor performing the work to implement interim controls and assess actual employeeexposures during the work in accordance 29 CFR 1926.62. Based on the lead results provided bythe laboratory testing, 29 CFR 1926.62 is invoked during any activities that disturb the paint(e.g., abrasive blast cleaning, scraping, burning, and grinding).



11

It should be noted that other hazardous metals can also be present in the coating. Anydisturbance of paint containing heavy metals in addition to lead must be performed in accordance

with the requirements of the applicable OSHA standards.

In addition, containment will be required for the protection of the environment and the

public, and the hazardous waste must be properly managed.

Caulkine

Caulking should be considered for crevice areas, particularly those where pack rust has

already formed. The caulking can be applied prior to the finish coat or after the finish coat. ffapplied before the finish coat, productivity can be affected as the caulking may take a few days to

cure prior to painting. If applied after the finish coat, it will be visible and can pick up and retain

dirt. A compromise is to apply the caulking after the finish coat and follow up with a brush coat

of frnish on the caulking a few days later to conceal it and to prevent dirt pick-up.

Cables

The lift span operates using a cable system. Measures to protect the cables duringcleaning and painting must be taken, such as wrapping cables in a sheet rubber sleeve. A non-

metallic abrasive may be preferred in these areas to prevent corrosion of any stray abrasive on the

cables that may work its way under the protective shield. Any inaccessible areas where abrasive

blasting can not be performed should be coated with a more surface tolerant system such as

epoxy mastic or calcium sulfonate alkyd.

Wood Deck

The bridge has wood plank sidewalks along both sides of the bridge. The deck on top ofthe towers is also made of wood planking. Measures to protect the wood planking abrasive blastcleaning and painting must be taken.

Open Steel Grid Deckine

The existing open steel bridge decking is in good condition overall. When blasting and

painting members adjacent to and below the bridge decking, the preferred method is to removethe bridge decking while blasting and painting the support steel and reinstall the bridge deckingwhen painting is complete. This allows blasting and painting for the portions of steel that wouldbe below the bridge decking and since the bridge decking itself is in good condition it would notneed to be painted. If the bridge decking remains in place, the edges will get blasted whileblasting the support steel. These areas along the edges would require coating. Due to the good

condition of the bridge decking, full blasting and painting of all of it would not be required.

HDR Engineering, lnc.Memorial Bridge


t2

Containment

The bridge crosses a navigable waterway. The lift span will have to remain operationalduring all maintenance work to allow boat traffic to pass. Containment of the lift span andtowers will need to allow for raising the lift span.

OPINION OF PROBABLE COATING REPLACEMENT COSTS

A cost analysis was prepared for various options for maintaining the existing coatingsystem. This analysis involved making various assumptions, based upon KTA and industryexperience, of how a contractor might staff and proceed with the aforementionedrecommendations. The site visit revealed limited space would be available to a paintingcontractor for equipment staging. Crew sizes, production rates, material and equipmentrequirements are evaluated and man-days and project-days are calculated. From the estimatedproject duration, costs associated with labor, materials, and equipment are factored in and thecosts are developed. Overhead and profit are added as a multiplier to the base cost. For thepurposes of this opinion of probable coating cost, labor was considered to be prevailing wage andequipment was calculated with rental rates.

Production days were calculated from the square footage of paintable steel surfaces andan allocated production rate. The surface areas for the bridges were performed from the provideddrawings. The Memorial Bridge is estimated to be 306,700 square feet. The requirements forenvironmental protection, worker health and safety, waste disposal, and containment areincluded. Maintenance and protection of traffic during construction was not included in thecosts. Finally, a variance multiplier is used on the final cost to develop aÍange of anticipated bidprices. This multiplier allows for the variations in contractor bidding techniques, newtechnology, and scheduling of the work within the painting season. The opinion of probable costto perform total removal and replacement of the coating on the Memorial Bridge ranges from$4,550,000 to $5,500,000 for each. Total removal and replacement would take approximately 10months total production for the bridge.

Opinions of probable construction costs are prepared on the basis of KTA's experienceand qualifications and represent KTA's judgment as field professionals generally familiar withthe industry. However, since KTA has no control over the cost of labor, materials, equipment, orservices furnished by others, over contractor's methods of determining prices, or overcompetitive bidding of market conditions, KTA cannot and does not guarantee that proposals,bids, or actual construction costs will not vary from KTA's opinions of probable cost.



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